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Catalytic N2O decomposition on Pr0.8Ba0.2MnO3 type perovskite catalyst for industrial emission control
No full textBa substituted PrMnO3 type perovskite catalysts (Pr1−xBaxMnO3 with x = 0.1–0.4) have been studied for
N2O decomposition reaction. These catalysts were prepared by a combination of co-precipitation and
impregnation methods. They are characterized in detail by means of XRD, BET-SA, SEM, EDX, O2-TPD, H2-
TPR and XPS analysis. The catalytic activity of Ba substituted PrMnO3 catalyst was observed to be relatively
better than the bare catalyst, thereby showing the promotional effect of barium, and Pr0.8Ba0.2MnO3 with
20 mol% substitution was found to be the optimized composition. The Pr0.8Ba0.2MnO3 catalyst composition
was also prepared in supported form using ceramic honeycomb by following in situ co-precipitation
method and tested for N2O decomposition reaction under simulated feed conditions. Supported catalyst
shows 92% conversion of N2O at 550 ◦C with a maximum of 0.0984 mmol of N2O decomposed per gram
of the catalyst, per unit time in the presence of NO and O2, which was higher than that obtained for
unsupported catalyst. O2-TPD studies inferred that Ba incorporation results in increase of Mn4+/Mn3+
ratio of PrMnO3 catalyst, thereby confirming the substitution of Ba in perovskite structure. TPR studies
also provided the clear evidence to this effect. This improved redox property of Ba substituted perovskite
catalyst was correlated to its enhanced catalytic activity for N2O decomposition
Hydrogen delivery through liquid organic hydrides: Considerations for a potential technology
No full textCarrying hydrogen in chemically bounded form as cycloalkanes and recovery of hydrogen via a subsequent dehydrogenation reaction is a potential option for hydrogen transport and delivery. We have earlier reported a novel method for transportation and delivery of hydrogen through liquid organic hydrides (LOH) such as cycloalkanes. The candidate cycloalkanes including cyclohexane, methylcyclohexane, decalin etc. contains 6 to 8 wt% hydrogen with volume basis capacity of hydrogen storage of 60e62 kg/m3. In view of several advantages of the system such as transportation by present infrastructure of lorries, no specific temperature pressure requirement and recyclable reactants/products, the LOH definitely pose for a potential technology for hydrogen delivery. A considerable development is reported in this field regarding various aspects of the catalytic dehydro-genation of the cycloalkanes for activity, selectivity and stability. We have earlier reported an account of development in chemical hydrides. This article reports a state-of-art in LOH as hydrogen carrier related to dehydrogenation catalysts, supports, reactors, kinetics, thermodynamic aspects, potential demand of technology in field, patent literature etc
PHOTOCATALYTIC HYDROGEN GENERATION BY ETHANOL ASSISTED WATER SPLITTING REACTION USING MIXED OXIDE OF Ba AND Mn
No full textVisible light active BaMnOx type photocatalyst was synthesized by using sol-gel method. The photocatalyst was characterized by
X- ray diffraction, BET-SA, and UV-visible diffused reflectance spectroscopy (UV-DRS). BaMnOx photocatalyst exhibited an optical band gap
of 2.9 eV with the absorption predominantly in visible region of the light spectrum. The crystallite size of BaMnOx is 24.63 nm as calculated
by the Debye Scherer equation. The BET surface area value for BaMnOx photocatalyst was found to be 16.2 m2/g. The photocatalytic hydrogen
generation was carried out by using Pt as co-catalyst and ethanol as a sacrificial donor. Hydrogen generation was investigated by ethanol
assisted water splitting reaction under visible light irradiation, using a compact glass reactor and tungsten lamp as a source of visible
light. The rate of photocatalytic hydrogen evolution was observed to be 7463 μmol.g-1.h-1 of Pt-BaMnOx
photocatalyst
Nano-ferrites for water splitting: unprecedented high photocatalytic hydrogen production under visible light
No full textIn the present investigation, hydrogen production via water splitting by nano-ferrites was studied using
ethanol as the sacrificial donor and Pt as co-catalyst. Nano-ferrite is emerging as a promising
photocatalyst with a hydrogen evolution rate of 8.275 mmol h�1 and a hydrogen yield of 8275 mmol h�1
g�1 under visible light compared to 0.0046 mmol h�1 for commercial iron oxide (tested under similar
experimental conditions). Nano-ferrites were tested in three different photoreactor configurations. The
rate of hydrogen evolution by nano-ferrite was significantly influenced by the photoreactor
configuration. Altering the reactor configuration led to sevenfold (59.55 mmol h�1) increase in the
hydrogen evolution rate. Nano-ferrites have shown remarkable stability in hydrogen production up to
30 h and the cumulative hydrogen evolution rate was observed to be 98.79 mmol h�1. The hydrogen
yield was seen to be influenced by several factors like photocatalyst dose, illumination intensity,
irradiation time, sacrificial donor and presence of co-catalyst. These were then investigated in detail. It
was evident from the experimental data that nano-ferrites under optimized reaction conditions and
photoreactor configuration could lead to remarkable hydrogen evolution activity under visible light.
Temperature had a significant role in enhancing the hydrogen yield
Effective cleanup of CO in hydrogen by PROX over perovskite and mixed oxides
No full textPreferential oxidation of CO (PROX-CO) from hydrogen has been carried out over various
oxides and perovskite catalysts namely CeO2, CuLaO2eCeO2, La2CuO4. Further, effect of
loading of a small quantity of Pt in catalysts 0.1 wt% Pt/CeO2, 0.1 wt% Pt/La2CuO4, 0.1 wt%
Pt/CuLaO2eCeO2 was examined with respect to its activity for PROX-CO. In order to
improve the surface area of La2CuO4 a chitosan complex method was used for synthesis.
The catalysts were characterized using XRD, SEM and BET-SA techniques. Chitosan
complex method results in pervoskite with pure phase, porous structure and higher
surface area of 16.3 m2/g compared to that of 3.8 m2/g obtained by co-precipitation
synthesis method. La2CuO4 exhibited a considerable activity for CO oxidation with
conversion of 91.7%. Whereas, 0.1 wt% Pt/CuLaO2eCeO2 catalyst exhibited CO conversion
of 94.1% and selectivity of 87.1% at reaction temperature of 320 �C. The improved CO/H2
selectivity may be attributed to the promotion of water gas shift reaction at the interface of
Pt-metal oxide besides the relatively higher oxidation activity of the metal oxides. The
catalysts reported in this study with relatively higher CO conversion and selectivity with
lower value of l ¼ 0.3 exhibit potential for effective cleanup of hydrogen gas to remove CO
for fuel cell applications
Cellular alterations and modulation of protein expression in bitumen-challenged human osteoblast cells
No full textPurpose
There are many arguments on the carcinogenic potential of bitumen extract. The mechanism of bitumen-induced damage is not well understood at the molecular level. Therefore, in the present study, cell-transforming and tumor-inducing potential of bitumen extract was studied using in vitro [human osteosarcoma (HOS) cells] and in vivo [nude and severe combined immunodeficiency (SCID) mice] models.
Methods
Gas chromatography/mass spectrometry (GC/MS) analysis was carried out to find out the existence of carcinogenic compounds in the bitumen extract. Cell transformation test, anchorage independence assay, karyotyping assay, tumorigenicity assay, and 2-DE analysis were used to find out the effect of bitumen using the in vitro and in vivo models.
Results
GC/MS analysis showed the existence of carcinogenic compounds in the bitumen extract. HOS cells were treated with different concentrations (25, 50, and 100 μl/ml) of bitumen extract. Compared to the parental HOS cells, bitumen transformants (HOS T1 and HOS T2) showed the characteristics of anchorage independency, chromosomal anomaly, and cellular transformation. Interestingly, bitumen transformants were not able to form tumor in nude/SCID mice. Proteomic analysis revealed the existence of 19 differentially expressed proteins involved in progression of cancer, angiogenesis, cell adhesion, etc.
Conclusions
Exposure of bitumen extract to HOS cells results in the cellular transformation similar to cancer cells and can modulate proteins involved in the progression of cancer. We state that the non-tumorogenic potential of bitumen transformant in nude/SCID mice can be attributed to the downregulation of galectin-1, chromodomain helicase DNA-binding protein 1-like gene, and membrane-associated guanylate kinase 2 protein
Interaction of Fish with Pathogenic Microorganisms and Application of Phages for their control - A review.
No full textThe present condition of aquacultural
industry is influenced by the economical losses due
to various aquacultural diseases causing fish mortality.
The present review provides benchmark information
related to application of bacteriophages in aquacultural
industries over available traditional treatment
procedures like antibiotics and chemotherapy. The
traditional methods are mostly less advantageous due
to development of resistance, non-specific targeting of
bacteria including intestinal microflora, etc. In short
here we discuss the interaction between fish, bacteria
and their phages in order to have an alternate treatment
method for the pathogens responsible for aquacultural
diseases
Effect Of Metal Ions And Chemical Solvents On The Adsorption Of Salmonella Phage On Salmonella Choleraesuis Subspecies Indica WAMAN NARAYAN PAUNIKAR*, SWAPNIL GANESH SANMUKH AND TARUN KANTI GHOSH
No full textThe effect of metal ions and chemical solvents on the adsorption of Salmonella phage isolated from sewage water on Salmonella choleraesuis subspecies indica showed how
they interfere in the phage-host interaction process in the aquatic systems. Already the studies regarding the effect of metal ions had been done, but still the adsorption properties of different phages differ with ionic concentration. In present experiment, we used different concentrations to study their effect on phage-host interaction. It was observed that the concentration that supports higher phage adsorption gives higher
plaque count and there is also a possibility of enhancement and/or irregular phage infection in presence of some heavy metals and chemical solvents. The presented work
deals with the role of different metal ions and chemical solvents at lower concentration on the adsorption and infection process of bacteriophages to their hosts. The data
generated from these studies is helpful in understanding the impact of different metals and chemical compounds on the microbial growth and behavior in aquatic system
Effect of zeolites on thermal decomposition of ammonia borane
No full textChemical hydrides due to their light weight and high storage capacity are considered to be promising hydrogen storage materials for both mobile and stationary applications. Ammonia Borane (AB) is a novel material with very high hydrogen content (19.6 wt %) per mass. The decomposition of AB takes place in three steps at desorption temperatures of about 100 _C, 140 _C and above 1000 _C respectively releasing 1 mol of hydrogen in each step. The major obstacle towards the use of AB as a hydrogen store is its irreversibility and slow kinetics. With the additives the decomposition temperature could be reduced and the kinetics can be improved. Effect of addition of Zeolites on decomposition of Ammonia Borane at different temperatures is reported in this paper. It was observed that the kinetics behaviour is greatly affected by addition of Zeolites with considerable reduction in the induction or warm-up period
Effective cleanup of CO in hydrogen by PROX over perovskite and mixed oxides
No full textPreferential oxidation of CO (PROX-CO) from hydrogen has been carried out over various oxides and perovskite catalysts namely CeO2, CuLaO2eCeO2, La2CuO4. Further, effect of loading of a small quantity of Pt in catalysts 0.1 wt% Pt/CeO2, 0.1 wt% Pt/La2CuO4, 0.1 wt% Pt/CuLaO2eCeO2 was examined with respect to its activity for PROX-CO. In order to improve the surface area of La2CuO4 a chitosan complex method was used for synthesis. The catalysts were characterized using XRD, SEM and BET-SA techniques. Chitosan complex method results in pervoskite with pure phase, porous structure and higher surface area of 16.3 m2/g compared to that of 3.8 m2/g obtained by co-precipitation synthesis method. La2CuO4 exhibited a considerable activity for CO oxidation with conversion of 91.7%. Whereas, 0.1 wt% Pt/CuLaO2eCeO2 catalyst exhibited CO conversion of 94.1% and selectivity of 87.1% at reaction temperature of 320 _C. The improved CO/H2 selectivity may be attributed to the promotion of water gas shift reaction at the interface of Pt-metal oxide besides the relatively higher oxidation activity of the metal oxides. The catalysts reported in this study with relatively higher CO conversion and selectivity with lower value of l ¼ 0.3 exhibit potential for effective cleanup of hydrogen gas to remove CO for fuel cell applications